Shutter systems are well known. Such systems are typically used on an s-needed basis to cover and protect windows, doors, and other openings in buildings from flying debris and other displacement forces that result from strong storms, such as severe thunderstorms, hurricanes, tropical storms, typhoons, and tropical cyclones. Such systems may also be used on a more regular basis (e.g., daily) to provide privacy, noise reduction, and security or intrusion resistance.
Basic shutter systems include a barrier assembly made up of corrugated steel or aluminum alloy panels that are fastened over the wall openings using threaded bolts that screw into anchors recessed in the walls of the building. Other basic systems also use corrugated panels, but instead of recessed anchors, such systems use rails that are secured to the building above and below the opening. The panels are inserted along the rails and are secured to the rails with bolts and wing nuts.
While storm panels are useful in protecting the building's openings, they have certain disadvantages. For example, steel panels are relatively heavy, weighing approximately two pounds per square foot. Thus, such panels become difficult to install on a two or three story dwelling, particularly when the homeowner must carry each panel necessary to cover the upper story windows up a ladder and onto a roof. Making the upper story installation even more difficult is the common use of wavy, Spanish tile roofs on many homes in geographical areas that are more prone to be in the paths of hurricanes or other strong storms.
Other more sophisticated storm shutter systems are also commercially available. One such system is referred to as an accordion shutter system. In an accordion shutter system, rails are installed above and below the wall opening, and a flexible, corrugated panel is permanently installed just outside each vertical end of the opening such that the panels, when deployed, can slide in the track created by the rails. When not in use, the panels are in a collapsed or compressed state and reside adjacent the vertical ends of the opening. To use, the user manually pulls or deploys each panel toward the center of the opening and locks the two panels together with a small padlock or other locking mechanism to keep them in place. When the storm has passed or use is otherwise no longer necessary or desired, the lock is removed and the user manually pushes or retracts the panels into their collapsed positions adjacent the vertical ends of the opening. Since the accordion panels are permanently installed, they need not be physically carried to and from their intended location before and after use.
Another more sophisticated shutter system is commonly referred to as a roller system or a rolling shutter system. In this system, the panels and anchors or rails of basic and accordion systems are replaced with a different barrier assembly made up of a series of interlocking steel or aluminum alloy slats that are wound around a motorized roller tube or reel. The roller tube resides in a housing that is mounted to the building just above the opening to be protected. Guide tracks are also mounted on each vertical end of the opening to guide the movement of the slats during deployment and retraction.
The motor of the rolling shutter system is electrically controlled and deploys the slats to cover the building's opening upon activation thereof. The deployment or lowering of the rolling shutter is based on the free fall of the interlocked slats primarily from the force of gravity while the roller tube rotates in one direction. Subsequent activation of the motor causes the motor to rotate the roller tube in an opposite direction to retract the slats and restore them on the roller tube. A motorized roller and its associated housing are permanently installed above every opening to be covered by the system. Dependable operation of the rolling shutter system relies on the ability of the slats to freely travel in the guide tracks without obstruction from pins, stems, or any other integrated components of the tracks.
While rolling shutter systems are very convenient forms of storm protection and security, they have their limitations. For example, the exertion of sufficiently strong displacement forces against the slats can cause the slats to deflect or bow excessively and thereby dislodge from the guide tracks, exposing the wall opening to flying debris or an intruder.
Various approaches have been proposed in order to try to prevent such dislodgement of the slats. One such approach is disclosed in U.S. Pat. No. 5,839,493 issued to Quasius. Quasius describes a rolling shutter and retention assembly in which stop elements are inserted into the ends of the shutter slats and the guide tracks include angled retention surfaces. When the slats are bowed as a result of displacement forces, the stop elements (e.g., screws or nails) engage the retention surfaces of the guide tracks to prevent or substantially impede dislodgement of the slats. While the Quasius system provides a mechanism for reducing the likelihood of slat dislodgement during application of displacement forces, the Quasius system requires stop elements to be inserted into the ends of the slats during fabrication of the shutter system, thereby increasing the overall cost and complexity of the system. In addition, the stop elements of the Quasius system are made of steel and, therefore, do not recover from bending that may result from the application of strong displacement forces against the slats. The stop elements' failure to recover from bending could produce an obstruction in the guide tracks, thereby negatively impacting the movement of the slats during subsequent operation of the system. To avoid such obstruction, the stop elements may require replacement, which, if not performed properly, could reduce the usefulness of the system.
Another slat dislodgement prevention approach is disclosed in German Patent Application Publication No. DE 2709029A1. Such publication describes a roller shutter that includes a guide track having one or more stems extending perpendicularly from respective shanks of the track. The slats of the shutter system have matching recesses to accommodate the extending stem(s), while leaving room for play. While the system described in the German publication provides a mechanism for reducing the likelihood of slat dislodgement without the need for stop ends to be inserted in the slats, such system requires the slats to operate integrally with the perpendicularly oriented guide rail stem. However, the guide rail may not be perfectly vertical due to normal architectural tolerances in the building to which the guide rail is attached. As a result, the guide rail stem may slightly obstruct the deployment of the slats, particularly when the shutter system is used on a daily basis for, for example, security and privacy reasons.
Therefore, a need exists for a shutter system and barrier assembly for use in connection therewith that substantially reduces the likelihood of slat dislodgement in the presence of severe displacement forces without requiring stop ends to be inserted into the ends of the slats and without requiring integral operation of guide track stems and slat recesses.